Scientists in North Carolina have discovered a genetic variation that could predispose people to depression and may help explain why some people who develop the condition get no relief from drug treatments.

The findings, posted yesterday in the online edition of the journal Neuron, may allow researchers to develop a test for genetic vulnerability to depression and to create more effective treatments.

"The results need to be replicated, but they suggest that we may be able to personalize the treatment of depression," said Dr. Thomas Insel, director of the National Institute of Mental Health, which helped finance the study. "We might be able to predict, based on the presence of this gene variation, whether someone will respond to certain antidepressants."

Dr. Marc Caron and Dr. Xiaodong Zhang, biologists at Duke University Medical Center, led a team of researchers who identified a mutation of a single gene that greatly reduced the amount of serotonin produced by brain cells. Serotonin is a chemical messenger active between neurons, and it has a powerful effect on mood.

Although scientists do not yet fully understand how the serotonin system works, higher circulating levels of it are associated with lighter moods. Antidepressant drugs like Prozac and Zoloft help lift feelings of despair in some people by prolonging the action of serotonin, experts say.

The researchers tested for that gene variation in 87 people with depression, and found that 10 percent had it - a significant genetic correlation, for a disorder that is influenced by multiple genes. They found that less than 1 percent of a comparison group without depression had the mutation.

In previous work, the scientists had shown that mice that have the same genetic variation have significantly reduced brain levels of serotonin. The mutation causes about an 80 percent drop in serotonin production in laboratory tests.

This is the first mutation that actually reduces production of serotonin, a factor linked to anxiety, depression and other mental troubles, Dr. Caron said.

There are very few posts on this thread. Other than yours, they are derisive. That just tells me that there are many who HAVE dealt with serious depression. It's not uncommon, and those who are dealing with it should NOT have a scarlet "D" branded upon them.

Those who try to make a joke of this subject have no understanding of neurobiology and have a basic fear of the subject. They have the same attitude that liberals have who don't understand conservatives. In otherwords, they don't want to know.

11
posted on 12/09/2004 11:50:15 PM PST
by SoCalPol
(Hey Chirac, Call Germany Next Time. They Know The Way To Paris)

I'm not saying serious depression doesn't exist - I've dealt with it myself in the past, so I'm fully aware of the implications.

I'm just critical of this stance that is implied whenever genetic research pops up about any biological phenomonon, that tries to paint this portrait of genes being the total, absolute, and immutable determinants of the phenomenon.

I could have told them there was a family disposition towards it. You just need to trace my family history ( depression, bipolar syndrome, ADD() and my husband's family history (add and chronic not as deep depression)

This is no more to be poo-pooed than to say it's true that certain families have a predisposition to alcoholism, which some do (add that to my family, too!) And I wouldn't be surprised if it turns out that low alcohol tolerance and serotonin mechanisms are linked, at least some of the time.

Now, this doesn't excuse behaviors, mind you. A person who has a predisposition or family history of addiction better be careful around things like alcohol.

But these things are real, every bit as real as other family genetic tendencies, such as type II diabetes which absolutely runs in families, some of the degenerative diseases, or even hemophilia.

Don't know why people think that just because it affects your mental state it might not be a physical illness.

A friend of mine recently developed a vitamin b-12 malabsorption problem, what in the old days they used to call pernicious anemia. First symptom? Everybody thought she was developing dementia, alsheimer's or something. Now she gets b-12 shots and she's almost back to normal.

After you've ruled out the physical, treated the underlying symptoms, then you can find out who's using what to be whiney just because. And there are people who do that. But if you haven't had clinical quality symptoms - don't think that these might not have physical causes. And they do run in families, sometimes.

The body and brain are composed of a billion moving parts, all working together in concert.

It always amazes me when others refuse to believe that some people are burdened with machines that have been tooled with less than optimal fault tolerances for every single part.

The tiniest invisible thing can alter body comp, psychological disposition, the ability to ward off disease, and more. We have barely scratched the surface in terms of understanding and when we do, it will still take skill beyond the average person to apply the knowledge.

For some to recognize a physical problem and not one of character may be afflicting an individual, the physical problem must be something they understand. Something as complex as this is too difficult for them, so they comfort themselves with simple platitudes.

They will continue to yell "buck up" unless they are confronting somebody who has lost their arms and legs. The guy missing an enzyme, or sporting a gene defect, is normal and should act like it as far as they can tell.

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